Showing papers on "Acetic acid published in 1979"

Catalytic preparation of ethyl acetate

Abstract: In a process for the preparation of ethyl acetate by vapor phase reaction of ethylene with acetic acid, the improvement which comprises conducting said reaction in the presence of a catalytic amount of a solid, ion-exchange fluoropolymer comprising sulfonic acid moieties.

Effect of Iron on Conversion of Acetic Acid to Methane During Methanogenic Fermentations

Abstract: Addition of iron (as a solution of reagent grade FeCl2, up to 20 mmol/1) to a methanogenic culture utilizing acetic acid markedly increased conversion of acetic acid to methane. The optimum soluble iron concentration was between 0.2 and 2 mM, with higher concentrations becoming slightly less stimulating. Most of the iron added precipitated within days after addition (mostly as ferrous carbonate or phosphate). Conversion of acetic acid to methane in liquid from municipal sewage digesters and from laboratory food processing waste digesters was also increased markedly by addition of iron. Results indicate that optimization of the conversion of acetic acid to methane in methanogenic fermentations requires soluble iron levels many times higher than those often required for maximum growth and activity in microbial cultures.

Studies on Chitin. I. Acetylation of Chitin

Abstract: Chitin was converted into diacetylchitin and also into various kinds of acetylchitins. A fully acetylated chitin was prepared by the acetylation of chitin in acetic anhydride—methanesulfonic acid mixture at 0°C overnight, or in acetic anhydride—perchloric acid mixture at 0°C for 3 h. Variously acetylated chitins were prepared by similar procedures applying a calculated amount of acetic anhydride in glacial acetic acid. The reaction of alkaline chitin with acetic anhydride gave 0.3 acetylchitin (0.3 mol of –OH groups are acetylated per one N-acetylglucosamine residue), and heating this with anhydrous sodium acetate in acetic anhydride produced ca 1.1 acetylchitin. However, it was difficult to further improve the degree of acetylation by this alkaline method. The acetylation of chitin resulted in an increase of solubility in formic acid, and diacetylchitin was easily soluble even in 85-% aqueous formic acid. The analytical data showed that the chitin residue exists as a stable hemihydrate unless it is completely acetylated. Infrared absorption spectra for chitin and acetylchitins were also investigated.

Enumeration of bacteria forming acetate from H2 and CO2 in anaerobic habitats

Abstract: A method has been worked out that allows the detection and isolation of bacteria fermenting molecular hydrogen and carbon dioxide to acetic acid. The ratio of methanogenic to acetogenic bacteria in sludge and lake sediment samples has been found to be approximately 100 to 1. Acetogenic bacteria could not be detected in rumen samples.

Light insensitive physical developers.

Abstract: Within the pH range 2.5-6.5 tungstic acid (an isopolyacid) prevents the reduction of silver ions by ascorbic acid or hydroquinone more effectively than either gum acacia or other protective colloids. The colloid state of tungstic acid can be stabilized with nonionic detergents, especially with Triton X-100. For buffering the system a mixture of acetic acid and sodium acetate is optimal. Physical developers constituted on the basis of the observations are, in contrast to those commonly used in histology, light insensitive, and remain clear for about 30 min at mom temperature 2-5 times as long as the time required for development.

Betanine stability in buffered solutions containing organic acids, metal cations, antioxidants, or sequestrants

Abstract: The rate of betanine degradation as affected by monocarboxylic acids (lactic acid, acetic acid), metal cations (Fe+++, Cu++), antioxidants (ascorbic acid, α-tocopherol) and sequestrants (citric acid, Na2 EDTA) was studied. Betanine was extracted from beets using water, and purified by molecular exclusion and adsorption chromatography. Column packings used were Sephadex G-25, polyacrylamide, and polyvinylpolypyrrolidone. The effect of food additives on the rate of oxidation of betanine in buffered systems was determined using a modification of the active oxygen method. A betanine solution was placed in a reaction chamber, held at 75° C, and oxygen was passed through the solution at a rate of 3 ml/min. The half-life value of betanine at 75° C, pH 5.0 in a phosphate buffer was 48.0 ± 1.0 min (control). Addition of 100 ppm lactic acid had no effect on stability (41 ± 1.7 mm), while 5.9% acetic acid caused a decrease in stability (33.4 ± 1.9 min) possibly as a result of pH changes at elevated temperatures. Metal ions at a level of 100 ppm caused an increase in the degradation rate compared to that of the control with addition of iron resulting in a half-life value of 33 ± 1.4 min. Copper had the greatest effect, reducing the half-life value to 6.0 ± 0.2 mm. Neither 100 ppm ascorbic acid nor 100 ppm a-tocopherol affected the half-life value of betanine (45.3 ± 2.3 and 50.2 ± 3.4 min, respectively). Ascorbic acid at 1000 ppm decreased the halt-life value (32.3 ± 3.3 min), whereas 10,000 ppm citric acid and 10,000 ppm EDTA caused an increase in the half-life value of 1.5 times compared to that of the control (69.4 ± 3.1 and 70.7 ± 7.1 min). Both 100 and 1000 ppm citric acid had no effect on betanine stability.

Inelastic electron tunnelling spectroscopy (IETS) of carboxylic acids and related systems chemisorbed on plasma-grown aluminium oxide. Part 1.—Formic acid (HCOOH and DCOOD), acetic acid (CH3COOH, CH3COOD and CD3COOD), trifluoroacetic acid, acetic anhydride, acetaldehyde and acetylchloride

Abstract: A study of the inelastic electron tunnelling spectra (IETS) of formic acid, [2H2]formic acid, acetic acid, [2H4]acetic acid and trifluoroacetic acid shows that these chemisorb from the vapour phase on to plasma-grown aluminium oxide as surface-bound formates and acetates. Detailed vibrational mode band assignments are made and the carboxylates are deduced to be adsorbed symmetrically on, though not necessarily perpendicular to, the oxide surface. The plasma-grown oxide shows enhanced reactivity to acetaldehyde over bulk γ-alumina behaviour. Evidence is obtained for the involvement of two surface-site types in reaction with trifluoroacetic acid.

Process for preparing polyols

Abstract: The invention describes an improved process for preparing polyols by reacting a mono-epoxy compound such as propylene oxide with a hydroxyl-containing initiator compound such as glycerine in the presence of a catalyst, the improvement being that the catalyst is added in the form of a calcium, strontium or barium salt of an organic acid such as acetic acid. Polyols prepared by this process can be employed to prepare polyurethanes without removing the catalyst.

Some biologically important low molecular weight organic acids in the sediments of Loch Eil

Abstract: The isolation of biologically important low molecular weight organic acids from organically enriched sediments in Loch Eil, Scotland, was carried out by extraction of pore water with acidified ethyl acetate. High concentrations of acetic acid, up to 1.8 mg g-1 dry weight of sediment were found at Station E-24. Propionate, butyrate, valerate, lactate and traces of succinate were also found. Succinate was present in significant amounts, 42.2 μg g-1 dry weight of sediment at Station E-70, which received a higher input of organic matter than E-24. Both propionate and succinate were absent from a control station in the Lynn of Lorne where the sediment was low in carbon compared with Loch Eil. In experimental tanks, acetate levels increased as the input of organic carbon (as cellulose) was increased up to a load level of 1.5 g m-2 day-1. Above this, acetate decreased and succinate appeared. Succinate was not detected in low-loaded tanks. Experiments with sieved mud showed a vertical distribution of the different acids with depth. Lactate and succinate reached highest concentration in the 0 to 3 cm layer, acetate at 3 to 6 cm and propionate at 6 to 9 cm. The results are discussed in relation to the role of these acids as food sources and as indicators of biochemical pathways taking place in sediments with different carbon input levels.

Monensin and dichloroacetamide influences on methane and volatile Fatty Acid production by rumen bacteria in vitro.

Abstract: The effect of monensin (0 or 33 μg/g of diet) upon rumen fermentation in the presence and absence of methanogenesis was determined in vitro by using mixed rumen organisms continuously cultured for 17 days. Methane was inhibited by dichloroacetamide (DCA; 32 mg/day) or by a pH of 5.1. Monensin effected a significant decrease in the ratio of acetic to propionic acid in the presence or absence of methanogenesis. In the absence of methanogenesis, the decrease in the ratio of acetic to propionic acid was entirely the result of increased propionic acid, whereas in the presence of methanogenesis the decrease in the ratio was the result of a combination of decreased acetic acid and increased propionic acid. There was a complementary interaction between monensin and DCA on volatile fatty acid production (expressed as millimoles of carbon per day). Addition of monensin to DCA-treated cultures resulted in the production of more acid; however, monensin and DCA had no beneficial effect on total carbon formed as acid and gases as compared with nonsupplemented control cultures. The monensin and DCA also resulted in greater digestion of neutral detergent fiber and less accumulation of formic acid and hydrogen as end products than did DCA alone. l-Lactic acid was produced in small but significantly greater amounts by the low-pH cultures, which also had less volatile fatty acid carbon formed from the fiber fraction of the forage supplied.

A comparison of the vibrational structures of ethanol, acetic acid, and acetaldehyde adsorbed on alumina

Abstract: The adsorption on aluminum oxide of acetaldehyde (CH3CHO) and acetic acid (CH3COOH) has been studied by utilizing inelastic electron tunneling spectroscopy (IETS) to probe the vibrational structures of the surface species over the spectral range between 240 and 4000 cm−1. Results for temperatures between 295 and 475 K are compared with our previous IETS results for ethanol (CH3CH2OH) adsorption on alumina up to 575 K. Although all three hydrocarbons form acetate complexes with the surface under certain conditions, slight differences in bonding and structure are evident in the IET spectra. The formation of some bulk aluminum hydroxide is observed also in certain cases. Observed variations in surface concentrations, bulk hydration, and the nature of surface hydroxyl groups are related to previous experimental results. Mechanisms are substantiated for the initial adsorption and subsequent reaction of each hydrocarbon with the surface.

Must Acetic Acid and Ethyl Acetate as Mold and Rot Indicators in Grapes

Abstract: The threshold values of acetic acid and ethyl acetate were evaluated in white and red table wines. Musts were fortified to various levels with these two chemicals in order to determine their fate during yeast growth and fermentation. From these data the rejection levels of the compounds, when present in musts, were established for both red and white table wines. Grapes molded with a number of fungi were fermented and the rejection levels for ethyl acetate verified. These must rejection levels for ethyl acetate in white and red grapes were 60 and 115 mg/l respectively. For acetic acid in white and red musts the rejection levels were 1190 and 900 mg/l respectively.

Process for preparing terephthalic acid

Abstract: A process for the continuous preparation of pure terephthalic acid by oxidation of p-xylene with molecular oxygen in acetic acid solvent comprising conducting the oxidation at a temperature of 205° to 230° C in the presence of an oxidation catalyst comprising (a) a cobalt compound in an amount of at least 120 ppm and less than 200 ppm as cobalt based on the weight of solvent, (b) a manganese compound sufficient to provide a manganese to cobalt weight ratio of 05 to 15 and (c) a bromine compound selected from hydrogen bromide, cobalt bromide and manganese bromide in an amount of 200 to 1,000 ppm as bromine based on the weight of solvent, while the water content of the liquid phase of the reaction system is kept at 4 to 14 percent by weight

Process for producing two-carbon atom oxygenated compounds from synthesis gas with minimal production of methane

Abstract: A process for selectively preparing a mixture of two-carbon atom oxygenated hydrocarbons, namely, acetic acid, ethanol and acetaldehyde, by continuously contacting a gaseous reaction mixture containing hydrogen and carbon monoxide with a solid catalyst comprising rhodium in combination with one or more alkali metals selected from the group consisting of lithium, potassium, cesium and rubidium at reaction conditions correlated so as to favor the formation of a substantial proportion of such two-carbon atom products.

Reaction of Coordinated Phosphines. IV. Mechanism of Carbon-Phosphorus Bond Cleavage in Triarylphosphines and Trialkylphosphines by Palladium(II) Acetate

Abstract: Reaction of triphenylphosphine with an equimolar amount of Pd(OAc)2 in acetic acid at room temperature in the presence of styrene gave trans-stilbene(94%), H3PO4(0.8%), PhP(O)(OH)2(40%), Ph2P(O)(OH)(19%), and Ph3P=O(35%). Reactions of tributyl- and trioctylphosphine with Pd(OAc)2 in acetic acid at 90 °C yielded butene(20%) and octene(1-; 22%, 2-; 17%), respectively, as main products. The phenylation of some olefins with triphenylphosphine in acetic acid-d, as well as other features of the reaction lead to the conclusion that nucleophilic attack on coordinated phosphorus atom is the most probable pathway for the formation of the phenylation agent (phenylpalladium species) in the reaction system among the others, ortho-metallation and oxidative addition.

Analysis of some older Scandinavian formulations of 2,4-dichlorophenoxy acetic acid and 2,4,5-trichlorophenoxy acetic acid for contents of chlorinated dibenzo-p-dioxins and dibenzofurans.

Abstract: Ten samples of older formulations of 2,4,5-trichlorophenoxy acetic acid and 2,4-dichlorophenoxy acetic acid used in Sweden were analyzed for chlorinated dibenzo-p-dioxins and dibenzofurans. The analyses were performed with gas chromatography/mass spectrometry with a high resolution glass capillary column for maximum isomeric separation and sensitivity. The detection limit was 0.01-0.05 ppm. The amounts of contaminants were of the same order of magnitude as that found earlier in European samples with later production dates (late 1960s and 1970s).

Allylic oxidation of methyl 2-alkenoates.

Abstract: Allylic oxidation of methyl 2-alkenoates with chromium trioxide in a mixture of acetic anhydride and acetic acid afforded methyl 4-oxo-2-alkenoates.

p-Xylene autoxidation studies. Oxidation of cobalt(II) and manganese(II) acetates by peracids

Abstract: The stoicheiometric oxidations of both cobalt(II) and manganese(II) acetates in aqueous acetic acid by m-chloroperbenzoic acid are non-free radical processes, the former proceeding via a peracid·CoII2 complex to give an active form of cobalt(III) which rearranges to a more stable form, and the latter proceeding in an autocatalytic fashion via a peracid·MnIII2 complex to give, in the presence of excess peracid, manganese(IV).